Field of the Invention
In one of its aspects, the present invention relates to a radiation source module for use in a fluid treatment system. In another of its aspects, the present invention relates to a fluid treatment system incorporating a radiation source module.
Description of the Prior Art
Fluid treatment systems are generally known in the art. More particularly, ultraviolet (UV) radiation fluid treatment systems are generally known in the art.
Early treatment systems comprise so-called “open channel” reactors.
For example, U.S. Pat. Nos. 4,482,809, 4,872,980 and 5,006,244 (all in the name of Maarschalkerweerd and all assigned to the assignee of the present invention and hereinafter referred to as the Maarschalkerweerd Patents) describe gravity fed fluid treatment systems which employ ultraviolet (UV) radiation.
Such systems include an array of UV lamp modules (e.g., frames), which include several UV lamps each of which are mounted within sleeves that extend between and are supported by a pair of legs that are attached to a cross-piece. The so-supported sleeves (containing the UV lamps) are immersed into a fluid to be treated, which is then irradiated as required. The amount of radiation to which the fluid is exposed is determined by the proximity of the fluid to the lamps, the output wattage of the lamps and the flow rate of the fluid past the lamps. Typically, one or more UV sensors may be employed to monitor the UV output of the lamps and the fluid level is typically controlled, to some extent, downstream of the treatment device by means of level gates or the like.
The Maarschalkerweerd Patents teach fluid treatment systems that were characterized by improved ability to extract the equipment from a wetted or submerged state without the need for full equipment redundancy. These designs compartmentalized the lamp arrays into rows and/or columns and were characterized by having the top of the reactor open to provide free-surface flow of fluid in a “top open” channel. These designs were also characterized by disposing each individual elongate lamp (or elongate radiation source) such that the longitudinal axis thereof is substantially parallel to the direction of fluid flow through the open channel.
It is also known to dispose the lamps such that the longitudinal axis thereof is orthogonal to the direction of fluid flow through the open channel. For example, U.S. Pat No. 5,952,663 to Blatchley, III et al. (Blatchley) describes an apparatus for applying ultraviolet radiation dosage to fluids in an open channel. With particular reference to FIG. 12 in Blatchley, there is shown a fluid treatment channel containing a module having a series of vertically disposed lamps (14). Disposed on the sidewalls of the fluid channel are a series of fluid diverters (27). As shown, the arrangement of fluid diverters (27) is such that each fluid diverter (27) projects into the fluid treatment channel to the same extent. Such an arrangement is disadvantages since it results in relatively high fluid head loss and low treatment efficiency.
It is also known to dispose the lamps such that the longitudinal axis thereof is disposed at an oblique angle (i.e., non-parallel and non-orthogonal) with respect to the direction of fluid flow through the open channel. For example, Canadian patent application 2,872,607 to Morningstar et al. (Morningstar) describes an ultraviolet radiation (UV) water treatment plant comprising at least one module, which includes an array of elongate UV radiation lamps in a mount. The radiation lamps are disposed in parallel to one another and at an oblique angle with respect to the direction of water flow in the open channel. A base is provided to which at least one guide is fixedly connected, and at least one guide rail is provided that is connected to the mount. The guide rail is movably mounted in the guide.
The module described by Morningstar includes a serially offset base (i.e., disposed upstream or downstream of the array of elongate UV radiation lamps) having a centrally disposed mechanical lift mechanism which serves to translate the array of elongate UV radiation lamps in a direction away from the open channel for servicing, etc. A problem with this approach is that it is not possible to tightly arrange serial arrays of elongate UV radiation lamps because of the space required for the centrally disposed mechanical lift mechanism associated with each module. For example, it is not possible to arrange serial modules illustrated by Morningstar such that the distance between serial rows of elongate UV radiation lamps in an array in a single module is the same or less that the distance between rows of elongate UV radiation lamps in serially adjacent modules. The result is that the water treatment plant described by Morningstar requires a relatively large footprint of space to accommodate all necessary components. This is particularly problematic if a UV radiation water treatment system is being used to replace a conventional chlorine disinfection system.
It would be highly desirable to have a radiation source module and a fluid treatment is system that overcomes the above problems. More specifically, it would be highly desirable to have a radiation source module and a fluid treatment system that make it possible to arrange serial modules such that the distance between serial rows of elongate UV radiation lamps in an array in a single module is the same or less that the distance between rows of elongate UV radiation lamps in serially adjacent modules. This would allow for a reduction (compared to the module and water treatment described by Morningstar) in the footprint of space to accommodate all necessary components. This would be particularly advantageous if a UV radiation water treatment system is being used to replace a convention chlorine disinfection system.